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THE TOPLINE: The White House on Monday confirmed plans to try to bulk up defense spending while circumventing budget caps.

In an op-ed for Real Clear Politics, acting Office of Management and Budget Director Russ Vought wrote that the White House's budget will put more money into the Overseas Contingency Operations (OCO) account, which is not subject to budget caps, to increase defense spending.

"Making America safe and secure is the administration's top priority and the president's budget will reflect that," Vought wrote. "However, the budget will provide these investments while adhering to the spending caps already set in law. Additional needed defense resources will be designated as Overseas Contingency Operations (OCO) funds, which are not subject to the spending caps."

Vought did not specify how much will be put in OCO, but several reports previously said the administration could request as much as $174 billion for the account, a significant increase over this year's $69 billion for OCO.

Do the math: One wondering where $174 billion comes from need only do subtraction.

The administration wants a $750 billion defense budget for fiscal year 2020. The Budget Control Act caps fiscal year 2020 defense spending at $576 billion.

$750 billion minus $576 billion equals $174 billion.

No go: OCO is supposed to be a war fund that is only used for temporary expenses associated with the wars in the Middle East.

Over the years, though, it has increasingly been used for base budget items, with critics calling it a slush fund.

Ahead of his departure, Trump was upbeat about the summit, tweeting that he and Kim "both expect a continuation of the progress made at first Summit in Singapore."

"Denuclearization?" he asked.

Trump in a separate tweet said that Kim "realizes, perhaps better than anyone else, that without nuclear weapons, his country could fast become one of the great economic powers anywhere in the World."

Questions remain: Despite Trump's tweets, there remain several questions about what if anything Trump and Kim will accomplish this week.

We examined the uncertainty about the results of the summit over the weekend. Among the gaps that still remain between the United States and North Korea are basic questions, such as what denuclearization actually means.

Domestic distractions?: While Trump is Vietnam, House Democrats have lined up one of their most confrontational weeks with him yet since they took control of the chamber.

The House is expected to vote Tuesday on a measure overturning his emergency declaration to build a wall on the Mexican border.

The next day, the House Committee on Oversight and Reform will hear testimony from Trump's former personal lawyer Michael Cohen, setting the stage for some of the strangest split-screen cable news shots in U.S. history.

EX-SECURITY OFFICIALS REBUKE TRUMP ON EMERGENCY: Speaking of that emergency declaration, a group of 58 former national security officials issued a 13-page letter Monday condemning Trump's declaration.

The former officials argued the president's declaration undermines the purpose of the national declaration and will ultimately damage the country's security.

"We are aware of no emergency that remotely justifies such a step. The President's actions are at odds with the overwhelming evidence in the public record, including the administration's own data and estimates," the letter reads.

The former officials also argued that Trump's declaration has "further eroded his credibility with foreign leaders, both friend and foe."

"Should a genuine foreign crisis erupt, this lack of credibility will materially weaken this administration's ability to marshal allies to support the United States, and will embolden adversaries to oppose us," they wrote.

Who signed: Most of the signatories served during the Obama or Clinton administrations.

There were some Republican signatures, but they've been critical of Trump in the past. For example, signatory John McLaughlin, who held the No. 2 spot at the CIA under former President George W. Bush, has publicly spoken out against the president.

US CITIZEN HELD HOSTAGE IN YEMEN BROUGHT HOME: Trump said Monday a U.S. citizen held captive in Yemen for more than a year has been reunited with his family.

The president announced on Twitter that Danny Burch "has been recovered and reunited with his wife and children."

Background: Trump's announcement comes after reports last month that Burch had been freed and sent to Oman after being captured by Yemeni rebels in 2017.

Burch, who worked for the Yemeni Safer oil company and is married to a Yemeni citizen, was detained in September 2017 after taking his children to school.

His wife and colleagues told news outlets that he was abducted from his car by gunmen on a busy street in Yemen's capital of Sanaa.

Sanaa is controlled by Iran-backed Houthi rebels who are fighting against a Saudi Arabia-led military coalition backing Yemen's internationally recognized government.

Saudi Arabia's main partner in the coalition is the United Arab Emirates, and, in his tweets, Trump thanked the Emiratis for helping in "bringing Danny home."

"Danny's recovery reflects the best of what the United States & its partners can accomplish," Trump tweeted.

Context: The United States supports the Saudi-led coalition with logistics, intelligence sharing and arms sales. Congress has been increasingly opposed to that support amid fury of Saudi Arabia's killing of U.S.-based journalist Jamal Khashoggi.

The House this month passed a resolution to end U.S. military support to the coalition. The Senate is expected to take it up and pass it in the coming weeks.

The Senate Foreign Relations Committee is also scheduled to get a closed-door briefing on Yemen on Monday night from State Department and Pentagon officials.